/*
 * Copyright 2007 ZXing authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.zxing.client.result;

import java.util.regex.Pattern;

import com.google.zxing.Result;

/**
 * Implements the "MATMSG" email message entry format.
 *
 * Supported keys: TO, SUB, BODY
 *
 * @author Sean Owen
 */
public final class EmailDoCoMoResultParser extends AbstractDoCoMoResultParser {

    private static final Pattern ATEXT_ALPHANUMERIC = Pattern.compile("[a-zA-Z0-9@.!#$%&'*+\\-/=?^_`{|}~]+");

    @Override
    public EmailAddressParsedResult parse(Result result) {
        String rawText = getMassagedText(result);
        if (!rawText.startsWith("MATMSG:")) {
            return null;
        }
        String[] tos = matchDoCoMoPrefixedField("TO:", rawText, true);
        if (tos == null) {
            return null;
        }
        for (String to : tos) {
            if (!isBasicallyValidEmailAddress(to)) {
                return null;
            }
        }
        String subject = matchSingleDoCoMoPrefixedField("SUB:", rawText, false);
        String body = matchSingleDoCoMoPrefixedField("BODY:", rawText, false);
        return new EmailAddressParsedResult(tos, null, null, subject, body);
    }

    /**
     * This implements only the most basic checking for an email address's validity -- that it contains
     * an '@' and contains no characters disallowed by RFC 2822. This is an overly lenient definition of
     * validity. We want to generally be lenient here since this class is only intended to encapsulate what's
     * in a barcode, not "judge" it.
     */
    static boolean isBasicallyValidEmailAddress(String email) {
        return email != null && ATEXT_ALPHANUMERIC.matcher(email).matches() && email.indexOf('@') >= 0;
    }

}